Add missing test to WeakPtr

I discovered we have a weak pointer now and in my quest to understand how it works
I spotted case that was not tested:

1) ctor weakptr a
2) ctor factory f
3) ctor weakptr b
4) dtor weakptr b
5) dtor factory f
6) test a

Mostly because I thought I saw a mistake but alas it works as-is but still
the test is missing.

BUG=none
TEST= this is a test  
Review URL: http://codereview.chromium.org/7065030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@86526 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 14 insertions, 0 deletions

diff --git a/base/memory/weak_ptr_unittest.cc b/base/memory/weak_ptr_unittest.cc
index 6c2a7e8..c1a9526 100644
--- a/base/memory/weak_ptr_unittest.cc
+++ b/base/memory/weak_ptr_unittest.cc
@@ -80,6 +80,20 @@ TEST(WeakPtrTest, Multiple) {
   EXPECT_TRUE(b.get() == NULL);
 }
 
+TEST(WeakPtrTest, MultipleStaged) {
+  WeakPtr<int> a;
+  {
+    int data;
+    WeakPtrFactory<int> factory(&data);
+    a = factory.GetWeakPtr();
+    {
+      WeakPtr<int> b = factory.GetWeakPtr();
+    }
+    EXPECT_TRUE(a.get() != NULL);
+  }
+  EXPECT_TRUE(a.get() == NULL);
+}
+
 TEST(WeakPtrTest, UpCast) {
   Derived data;
   WeakPtrFactory<Derived> factory(&data);